Asphalt-surfaced roadways are built to facilitate vehicular travel. Depending upon usage density, base conditions, temperature variation, moisture levels, and/or physical age, the surfaces of the roadways eventually become misshapen and unable to support wheel loads. In order to rehabilitate the roadways for continued vehicular use, spent asphalt is removed in preparation for resurfacing.
Cold planers, sometimes also called road mills or scarifiers, are used to break up and remove layers of an asphalt roadway. A cold planer typically includes a frame propelled by tracked or wheeled drive units. The frame supports an engine, an operator's station, a milling drum, and conveyors. The milling drum, fitted with cutting tools, is rotated through a suitable interface with the engine to break up the surface of the roadway. The broken up roadway material is deposited by the milling drum onto the conveyors, which transfer the broken up material into haul trucks for removal from the worksite. As haul trucks are filled, they are replaced with empty haul trucks. The filled trucks transport the broken up material to a different location to be reused as aggregate in new asphalt or otherwise recycled. This transport process repeats until the milling process is finished.
Operators may wish to fill each truck to its maximum capacity before replacing it with an empty truck in order to reduce waste and improve efficiency. However, regulations that impose vehicle weight limits on some roadways may require operators to fill trucks below their maximum allowable capacity, and pay an associated fine when the weight limit is exceeded. Thus, operators visually estimate how much material has been loaded into a truck and, from that visual estimation, determine whether the truck has reached its maximum legal weight. Visual estimations, however, can be inaccurate.
One attempt to more accurately monitor truck filling is disclosed in U.S. Pat. No. 5,850,341 that issued to Fournier et al, on Dec. 15, 1998 (“the '341 patent”). In particular, the '341 patent discloses a system for measuring the weight of bucket loads of material that are emptied into a truck by a loading machine. Sensors attached to the loading machine measure hydraulic cylinder pressures and a lift angle associated with machine's loading equipment as bucket loads of material are lifted and emptied into the truck. A controller calculates the weight of each bucket load based on the cylinder pressures and the lift angle, and tracks a running sum of the weight of successive bucket loads emptied into the truck. When the truck is filled to a desired degree, the operator presses a button to store the truck's payload weight in a database and reset the bucket count for the next truck.
While effective in some applications, the truck filling monitoring system of the '341 patent may not address how to monitor material removal from machines that continuously mill material from a work surface during operation. Also, while the monitoring system of the '341 patent is only concerned with measuring the weight of loaded material, other measurements and/or determinations can be important in monitoring material removal.
The cold planer of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.